26-8-2008I. Podadera- IFMIF-EVEDA HEBT diagnostics- HB20081 HEBT Diagnostics for Commissioning,...

26-8-2008 I. Podadera- IFMIF-EVEDA HEBT diagnostics- HB2008 1

HEBT Diagnostics for Commissioning, Control and Characterization of the

IFMIF-EVEDA Accelerator

PY. Beauvais2, B. Brañas1, J.M. Carmona1, N. Chauvin2, A. Ibarra1, J. Marroncle2, A. Mosnier2, C. Oliver1, I. Podadera1

1CIEMAT2CEA-Saclay


IFMIF Goals

Characterization of materials envisaged for future fusion reactors.Study and analysis of the behaviour of materials under a high flux of neutrons (1018 n/m2/s).

P. Garin, IFMIF: status and developments, EPAC08, p. 974 (2008)

International Fusion Materials Irradiation Facility


IFMIF design

P. Garin, IFMIF: status and developments, EPAC08, p. 974 (2008)

Neutron flux density

Beam footprint at interaction point

Accelerator Target Irradiation module

Heat extraction by fast liquid Li

D+

Li fluxSamples

neutrons~1017 n/s

2 acc. In parallel

EM

bomb

Heat exchanger

Deuterons: 40 MeV 250 mA (10 MW)

20-50 dpa/y in 0.5 l

T: 250<T<1000℃

Facility availability >70%

20 cm

5 cm


IFMIF Accelerator

RF Power System175 MHz

High Energy Beam Transport (HEBT)Large Bore Quad & Dipoles

Superconducting HWRCW 175 MHz, HWR, 4 cryomodules, 40MeV

Radio Frequency Quadrupole (RFQ)CW 175 MHz, water cooled, 5 MeV

Ion InjectorCW ECR, Source, 140 mA D+, 95 keV, Magnetic LEBT to RFQ

EVEDA

Deuterons, 2 x 125 mA, CW, 40 MeV.

Target region: 20 cm horizontal x 5 cm vertical. Accelerator challenges

•Space charge.

•Beam instabilities.

•CW operation.

•Beam interception (activation).

•Shape of the beam footprint at the target.

Accelerator challenges

•Space charge.

•Beam instabilities.

•CW operation.

•Beam interception (activation).

•Shape of the beam footprint at the target.


EVEDA phase Engineering Validation and Engineering

Design of the IFMIF project


Goals•to validate the technical options with the construction of a prototype accelerator.

•to produce the detailed integrated design of the future IFMIF accelerator.

Main specifications•Installation in Rokkasho-Japan 2012-2013.

•manufacturing and tests of a prototype accelerator (1:1) with 9 MeV final energy.

•Deuterons, 125 mA cw, 9 MeV.

•Commissioning phase: 0.5 mA-125 mA, pulsed mode down to 200 ms, 0.1% duty cycle.

A. Mosnier, A. Ibarra, A. Facco, The IFMIF-EVEDA accelerator activities, EPAC08,

p. 3539 (2008)



Mockup courtesy of T. Trublet

Ion especies D+ /H2+ (tests)

CW current (min/max) 0.5/125 mA

RFQ output energy 5 MeV (β=0.0727)

HWR output energy 9 MeV (β=0.0975)

RF frequency 175 MHz

Bunch width (min/max) 0.1-3 ns

Duty factor (min/max) 0.1%/CW

Pulse length (min/max) ~100 s/CW

Beam power 1.125 MW


IFMIF-EVEDA AcceleratorIon source LEBT RFQ MS HWR DP+HEBT BD

•5 MeV for RFQ comissioning:

•From 0.5 mA to 125 mA.

•Pulsed and CW operation.

•9 MeV for HWR commissioning and beam characterization :

•From 0.5 to 125 mA.

•Pulsed and CW operation.

ECRIS Pulse characteristics

Tb~1000·tp

tr

tp

tf

tr >10-20 ustf >45 s

tp >100 s (200 us for stabilization)

DC=0.1%Tb > 0.1 s

Commissioning


HEBT beam diagnostics

BLM

BP

BLM

Q8 Q9

BLM BLM

Q5 Q6 Q7

Diagnostics plate

HWR01

Q10

Q11

Q12

BD

D1

RFQ

HW

RD

1

BD

EC

R+

LEB

TD

P

MS

3 m1 m 1 m 0.5 m0.5 m

1 m

4 mBLM

Shielding

IFMIF Profilers prototypes

1 m

1.5 m

•Characterization diagnostics: Diagnostics Plate+spectrometer.

•Beam Dump control: Halo, BLM’s position and transverse profile to control losses and power density profile on the cone (~200 kW/cm2).

•Beam Losses: BLM’s + DCCT and BPM’s transmission monitoring.

•Spectrometer: beam characterization (profilers), reduction radiation impact on the accelerator, controlled with BPM’s, DCCT’s transmission and BLM’s.


High Energy Beam Transport Line (HEBT)

HWR

Beam dump

Magnetic dipole (spectrometer)

TraceWin - CEA/DSM/DAPNIA/SACM

Position (m)9876543210

X (

mm

)

150

100

50

0

-50

-100

-150

QP1QP2QP3D1

QP4QP5D2

QP6QP7 QP8


Y (

mm

)

150

100

50

0

-50

-100

-150

QP1QP2QP3D1

QP4QP5D2

QP6QP7 QP8

rms beam envelope along the HEBT (from HWR up to Beam Dump)C. Oliver et al., HEBT for the IFMIF-EVEDA accelerator,

EPAC’08, p. 3041 (2008)

BPM5BPM6

TPM3

TPM-IFMIF

TPM2TPM1

QT1

QD2

QT3

BPM4

Diagnostics plate

SHM2

Bea

m d

ynam

ics

draft

DCCT2DCCT4

DCCT3


HEBT diagnosticsParameter Method Comments

EVEDA

1 AC current ACCT

2 DC current DCCT

3 Position Stripline BPM

4 Transverse Profile Gas fluorescence (FPM)

Gas ionization (BTPM)

5 Longitudinal Bunch Shape FCT,…

6 Bunch length BPM Frequency spectrum Or FCT,…

7 Beam Losses TBD Plastic scintillators, fission chambers...

8 Transverse Halo Metallic rings / scrapers

9 Mean energy TOF with BPM Or dedicated capacitive rings

10 Transverse emittance Quadrupole scan Space charge and beam losses limitation

11 Longitudinal emittance Buncher scan Space charge/ beam losses/ monitor limitation

12 Energy spread Spectrometer

IFMIF

13 IFMIF target transverse square profile

Gas ionization Big beam pipe aperture/ image borders

14 Gas fluorescence Big beam pipe aperture/ image borders

Essential for initial commissioning (HB2006):

CurrentPositionProfile


Diagnostics Plate

I. Podadera et al., EPAC’08, p. 1248 (2008)

BPM1

BPM2

BPM3FPM1

BTPM1

SHM1

DCCT1

ACCT1

Characterization of each important beam parameter for validation of the accelerator and commissioning of the RFQ

and the HWR cavities

Challenges

•Low β

•Debunching

•Radiation damage draft

Parameters

•DC current

•AC noise

•Centroid jitter

•Transverse profile (size and distribution)

•Halo

•Mean energy

•Bunch width


Low- image currentBeam

current

Image current

100 mm

150 mm

BP

M1

BP

M6

The fundamental harmonic is reduced almost 5 times from the

beginning to the end of the line. The higher harmonics dissapear…


Stripline Beam Position Monitors

Example for β=0.4

•Shorted stripline Beam Position Monitors along the HEBT (x6).

•β=1 approximation not longer valid (Shafer criteria)1

•Use for beam position measurement (probably at the fundamental harmonic due to the low signal at higher harmonics).

•Time of flight measurement (better accuracy than capacitive pick-up for offset beams)2.

•Bunch width measurements at DP using higher harmonics.

EM simulations

1R. Shafer, AIP BIW'93,319, p. 303 (1994)2S. Kurennoy, On Beam Phase Detectors for SNS LINAC, SNS 99-65 (1999).

Energy: 5/9 MeV

Position resolution: 10 m

Absolute precision: 100 m

Dynamic range: 0.5 mA- 150 mA

Position range: ± 30% aperture.

Linearity error: ±1%.

Phase accuracy: 1º-2º.

Phase resolution: 0.1º.

Energy: 5/9 MeV

Position resolution: 10 m

Absolute precision: 100 m

Dynamic range: 0.5 mA- 150 mA

Position range: ± 30% aperture.

Linearity error: ±1%.

Phase accuracy: 1º-2º.

Phase resolution: 0.1º.


Stripline Beam Position MonitorsFour-strip geometry optimization

C. Deibele, Matching BPM stripline electrodes to cables and electronics, PAC’2005, p.

2607 (2005).

quadsumdip ZZZZ 0

Optimization of the geometry parameters using the matching of the four strips with the

electronics.

Optimum for 175 MHz narrowband measurement

78 mm

swopt f

cl

112

Length optimization


MPS and thermal shock

0

0,05

0,1

0,15

0,2

0,25

0,3

0,35

0,4

0 5 10 15 20 25 30 35 40 45

Beam energy (MeV)

Alo

wa

ble

tim

e (m

s)

Copper

Iron

Alumina

0

1

10

0 5 10 15 20 25 30 35 40 45

Beam energy (MeV)

Alo

wa

ble

tim

e (

s)

DTL01-melting

DTL10-melting

DTL01-stress

DTL10-stress

melting

stressFormula for evaluation maximum heat density:2

According to the models, at SNS and J-PARC LINACs, the whole pulse injection would not be allowed.1,2

IFMIF accelerator stop limit (CDR): 10 μs

1R. E. Shafer, Internal documentation, SNS, 2001.

2 H. TAKEI and H. KOBAYASHI, J. Nucl. Sci. and Tech., 42, 12, p.1032-1039, 2005.

Maximum time before failure for 90º total beam impact::1

Time limits for different materials for IFMIF

But a 90º beam impact in the vacuum pipe is not realistic under normal operation conditions…


Transverse ProfileTwo non-interceptive methods based on interaction between gas in the chamber and deuteron beam are under design and will be installed at IFMIF-EVEDA.

Fluorescence (FPM)(CIEMAT development)

Ionization (BTPM)(CEA-Saclay development)

J. Marroncle et al., proceedings BIW’08, 2008

First experiments carried in Saclay with protons at 95 keV, 100 mA

Detector : microstrips, grid, resistors for a uniform electric field…

Detector mounted on its flange

Detector assembly in the vacuum pipe

Preliminary calculations: 1010 photon/s at 9 MeV, 125 mA

Energy: 5/9 MeV

Aperture: 100/150/200 mm.

Dynamic range: ±3σ.

Accuracy: 250 m, 5 A.

Rms precision: 100 m, 2 A.

Frequency bandwidth: 10 Hz.

Energy: 5/9 MeV

Aperture: 100/150/200 mm.

Dynamic range: ±3σ.

Accuracy: 250 m, 5 A.

Rms precision: 100 m, 2 A.

Frequency bandwidth: 10 Hz.


IFMIF profiler

Beam footprint at interaction point

•Key device for operation of the IFMIF accelerator.

•Control the overlap between both accelerators and the flat transverse profile.

•Several techniques have been already analyzed.1

•IFMIF profilers will be tested near the BD region at IFMIF-EVEDA (high neutron flux).

1E. Surrey et al., A beam profile monitor for IFMIF reference, EFDA TW5-TTMI-001 (2006)

20 cm

5 cm


Transverse emittance

TraceWin - CEA/DSM/DAPNIA/SACM


X (

mm

)

150

100

50

0

-50

-100

-150

QP1QP2QP3D1

QP4QP5D2

QP6QP7 QP8


Y (

mm

)

150

100

50

0

-50

-100

-150

QP1QP2QP3D1

QP4QP5D2

QP6QP7 QP8

C. Oliver et al., HEBT for the IFMIF-EVEDA accelerator, EPAC’08, p. 3041 (2008)

•Quadrupole scan in a free dispersion region (before spectrometer).

•Resolution affected by space charge (non-linear optics).

•Compromise between maximum size (beam losses) and minimum size (halo creation).


Conclusions•HEBT diagnostics will have to permit the safe transport of the IFMIF-EVEDA high-intensity deuteron beam from the HWR up to the beam dump.

•The beam will be fully characterized with a movable diagnostics plate and a spectrometer.

•Low beam energy and high intensity precludes the use of any interceptive diagnostics.

•The instrumentation placed near the BD will receive high radiation, it will be a good place to test the future IFMIF profiler.

•Electromagnetic pick-ups are challenging due to the low beta effect, the debunching process and the relatively high beam pipe diameter.

•An intensive R&D programme about the use of non-interceptive gas diagnostics (fluorescence & ionization) to monitor the transverse profile has started and its success is almost mandatory for the accelerator operation.

•Due to the high intensity, non-linear space charge forces make difficult the implementation of non-interceptive methods for the measurement of emittances and energy spread.


We want to thank the support and help of all the ASG

Thanks for your attention!!!


BLM

BP

150 11240 200 150 150400100 100 200 Min. 1000

DP preliminary configuration

BLM

All distances in mm

Stripline BPM 3

ACCT 1

DCCT 1

Fluorescence Transverse Profiler 1

Ionization Transverse Profiler 1

Segmented ring Halo monitor 1

Beam Loss Monitors TBD

Others (buncher, BSM, capacitive ring...) TBD


Mean energyMeasurements: Mean longitudinal energy

Energy: 5/9 MeV

Dynamic range: ± 20 % nominal E

Accuracy: ± 0.2 % nominal E

Rms precision: ± 0.01 % nominal E

Frequency bandwidth: 200 kHz

Measurements: Mean longitudinal energy

Energy: 5/9 MeV

Dynamic range: ± 20 % nominal E

Accuracy: ± 0.2 % nominal E

Rms precision: ± 0.01 % nominal E

Frequency bandwidth: 200 kHz


Spectrometer

Energy resolution obtained with a profiler resolution of 100 μm

E

(MeV)

ΔE

(keV)

β β+ Δβmax Φ (º)

Bρ

(T·m)

B

(T)

xout

(mm)(ΔE)res

(keV)

(ΔE)res/E0

(%)

5 100 0.0728 0.0735 20 0.458 0.229 4.61 2.71 0.04

9 50 0.0975 0.0977 20 0.614 0.307 1.29 3.88 0.04

•Protecting accelerator sensitive devices of neutron backscattering from the Beam Dump.

•Use for energy spread measurements

22 beam DE

beamE

0

Minimum 0.6% after the spectrometer

Analysis using Tracewin


Halo •Limit beam losses to 1 W/m (100 nA/m @ 9 MeV) along the accelerator

•For halo characterization due to beam mismatching and machine protection

•Preliminary idea: segmented ring

Measurements: Halo and machine interlock.

Energy: 5/9 MeV

Aperture: 100/200 mm

Accuracy: > 100 pA.

Rms precision: 10 pA.

Frequency bandwidth: 0.5 Hz

Measurements: Halo and machine interlock.

Energy: 5/9 MeV

Aperture: 100/200 mm

Accuracy: > 100 pA.

Rms precision: 10 pA.

Frequency bandwidth: 0.5 Hz


Beam loss monitors•Measurements: beam losses, transmission and machine protection.

•Energy: from 5 to 9 MeV

•Dynamic range: 104÷1.

•Accuracy: few A.

•Rms precision: ~50 pA.

•Frequency bandwidth: >5 Hz.

•Reaction time <10 μs.

•Azimuthally distributed around the beam pipe for beam position and halo monitoring.

Main candidates

•Plastic scintillators (>7-8 MeV)

•Microfission chambers

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26-8-2008I. Podadera- IFMIF-EVEDA HEBT diagnostics- HB20081 HEBT Diagnostics for Commissioning,...

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